Humans, The World's 'Superomnivores'

This is SCIENCE FRIDAY. I'm John Dankosky. Are you a fan of crunchy, crispy foods? Well, I am. In fact...

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DANKOSKY: Do you hear that? Yeah, that's a potato chip. It sounds pretty good, doesn't it? Now, no matter where you are in the world, you'll probably find that that crunch is popular with the locals. Think about it: tortilla chips, crispy chicken, fried calamari, biscotti, tempura, falafel, pekora - mmm, pekora.

But why is crispiness so universally appealing? Are we wired to like it? That's one of the many questions that my next addresses in his new book "The Omnivorous Mind: Our Evolving Relationship With Food." It's a history of humans and food from the days of foraging on the savannah to the creations of today's four-star chefs.

Let me introduce John S. Allen. He's also a neuroanthropologist at the Dornsife Cognitive Neuroscience Imaging Center at the University of Southern California. He joins us from a studio in Lexington, Kentucky, today. Welcome to SCIENCE FRIDAY, Dr. Allen.

JOHN S. ALLEN: Thank you for having me.

DANKOSKY: I'm just going to finish up this potato chip here. Now you write the appeal of crispy food appears, like our inalienable rights to life, liberty and the pursuit of happiness, to be self-evident. Why? Why so - why do we love these crispy foods so much?

ALLEN: Well, that's a good question. When I sort of started thinking about food and thinking about how we think about food, one of - I noticed a little quote from a Mario Batali, Iron Chef Mario Batali's cookbooks, where he said in effect there was an innate appeal of crispy and that it moved things on menus really quickly.

So I thought, well, taking that as a hypothesis, I mean, where does that come from or how do we justify that? And first thinking about, as you already mentioned, all those different cultures where crispy foods are found and which cross boundaries very readily, right, these are the foods that here in America, they come from other ethnic cultures that we've adapted to very quickly, and vice versa.

And so what are the different ways that we could explain that? And really when you look at it in detail, there are all different levels. And first, you know, thinking about our deep primate heritage, there's a lot of insect eating back there. And one of the natural crispy foods that we would have access to but which here in the West we don't particularly like so much, are insects, right.

They have a crunchy chitin shell, and if you eat them, you don't even have to cook them, although they're better if they're crisped up even more. Another source of - naturals source of crispy foods are plants and really, vegetation-type plants, not fruits but stalks and young leaves, and those can be also crispy, and other of our relatives eat those readily.

But those for us and for our closer relatives have been sort of what they would call fallback foods, less preferred compared to fruits and then later on meat. So there's that sort of very deep, potential appeal there.

More recently, in evolutionary terms - and by this I mean million and a half, two million years ago - people started to cook, or at least according to Richard Wrangham and some archeologists, who have found this evidence for deep cooking and the significance of cooking. And cooking introduces crispy, as well, right.

On the surface of cooked meat, on the surface of cooked - even of cooked vegetables, you get that browning, the Maillard reaction, and that is also crispy. So that's very deep and may also have a kind of deep evolutionary, that if you like that kind of food even more, you may have been more readily willing to adopt cooking.

So those sort of stories are quite, probably, relevant to our past. It's hard to prove some of them, but I think there's that aspect. So in those sort of deep evolutionary times, we do have this sort of crispy past.

More recently, or more in the contemporary sense, when you just ate that crispy potato chip, and we could all hear the crunch, well, in a sensory sense, crispy things expand what we usually think of as the food senses, right - taste, smell - but crispy brings sound into it. And if we eat a lot of something, you know, you start to habituate.

That's why, you know, you go to a Thomas Keller - you know, every day I go to Thomas Keller or Ferran Adria's very fancy places where they serve 20 or 30 courses, right. And part of that is to avoid the habituation, the sensory habituation that naturally comes in.

The other day I made a big batch of popcorn, and I'm sitting there on the couch shoveling it in, and I realized at a certain point, I didn't even taste it anymore, but I was still enjoying that crunch, crunch, crunch sound. And so that took longer to habituate that whole experience, and so I sort of perpetuated it.

And then, you know, we could even get even more cultural now in terms of our own culture because you ate a potato chip. You know, potato chips are dangerous foods, as we're all told, and yet - and for some people, there's nothing more enjoyable than doing something that is, you know, prohibited or illicit.

DANKOSKY: You know when they're dangerous is when you're trying to host a talk show. I'm still swallowing the potato chip.

ALLEN: Oh, I would imagine.

DANKOSKY: If you want to join us, 1-800-989-TALK, it's 1-800-989-8255, as we talk about why we love the foods we do with John S. Allen, the author of "The Omnivorous Mind: Our Evolving Relationship With Food." Now, it's not just about crunchy, though, about the sheer variety of foods that we eat. Are there any other animals that eat all these foods like we do?

ALLEN: Well, sure, there are really omnivorous animals. I mean, you know, we have dogs around us, and a lot of dogs will eat sort of anything beyond even what we would want. Pigs will eat almost anything and so on. But I put this term - I say super omnivore on us, which I got from an old anthropologist named Alfred Kroeber, who conceptualized culture as being super organic, and not in a supernatural sense, but just trying to get the idea of there's this sort of world that exists above the organic and that moves and has its own history and traditions.

And I think that our super omnivore is not just being able to eat all sorts of stuff in a biological sense, but we don't eat things, or we do eat things for cultural reasons, right. And so it's something that really transcends what we might think of as the omnivore of other animals.

DANKOSKY: Our closest relatives, like chimps and gorillas, they don't have this wide variety of foods. Why are we so closely related to people who just sort of like the one thing?

ALLEN: Well, I mean, chimps, they do like fruits, and they like meat, actually, too. They don't eat much of it; they don't get much of it. But all our closest relative apes live in a very circumscribed area. They live in tropical forests. And obviously, the thing that as long - people have said, whether you want to say it's get out of the trees and go to the savannah or in a more broad sense, you know, go out of the tropical forest and expand throughout the whole world, clearly an ability to acquire foods or prepare them and to eat them in all sorts of different environments has been critical to that evolutionary history.

DANKOSKY: Now, you write in your book there are some monkeys in Japan, they don't exactly cook their food, but they have a kind of a recipe for preparing food.

ALLEN: Well, this was out of a study that was actually started in the 1950s, very classic, sort of - where they would provision these Japanese macaques, who lived by the water, just to bring them out so they could observe them. But it became a study in their sort of cuisine and cultural transmission because it was found that one of them would take the potatoes and go to the water and wash them off because there was a beach, and I've been to this beach, and it's definitely a beach, and it's sort of annoying if your potato - and you didn't want to eat a bunch of sand.

So you go the water, and you wash it off. But it became apparent - two things. One is they like actually putting the potato into the salt water. And so there was obviously an appeal there. And the other thing about it was that this behavior then was transmitted through the group, especially in the younger monkeys.

Later on, they gave them wheat, and they would actually - the same female monkey, Emo(ph), would float handfuls of the wheat, take the handfuls with sand and through them in the water, and then the sand would drop, and the wheat would float.

And by the time I was there, which was some years after they started, they were still doing that. They cut it out because they get pretty big if you keep giving them all this food. But there's sort of - you know, there's obviously the ability to begin putting two things together, which really is sort of the beginning of a recipe.

And, you know, that history goes all the way up to the - you know, our creative history in food. And, if you think - you know, we think about the very creative things that you might see in the highest cuisine, but really there's probably nothing more important in terms of you might say small-C creativity was what you can do with food, what you can do with what's available and to make it palatable and edible.

DANKOSKY: Let's go to the phones. Paul(ph) is in Columbia, South Carolina. Hi there, Paul.

PAUL: Hi, hi, how are you?

DANKOSKY: Doing good, what's up?

PAUL: I just wanted to call and say that I love this topic. If you were to say, you know, you know when people say, well, let's go eat, OK, here are some potatoes, here's some broccoli, here's some fish. But it's just plain, old food that we've been eating for thousands of years, but here comes crunchy. Here comes the crunch of broccoli. Here comes the crunchy shrimp, the crunchy scallops, crunchy - I mean, you can make anything crunchy, really.

I mean, I don't know how to, but sure, chefs can. Crunchy potatoes, you know, crunchy bread, crunchy bread, and it is - I love it. I love anything that's crunchy. You feel that it's going to be something different and something good. I associate crunchy with something that tastes good.

DANKOSKY: Well, and that's I think what John Allen was talking about. Everyone loves the crunchy, and part of what he's talking about is that transformation process that humans have been able to do, to take something that's humble, like the potato, which doesn't really crunch all that much on its own, and do something just magical with it.

ALLEN: Exactly. When you take a potato, which is just a tuber, right? Of course, it's a - the potato we get thanks to our, you know, the South American - the Incas and others who developed the potatoes. But basically, it's a tuber, not a very appealing food. But you - if you modify it and - especially if you eliminate - and you make it - totally surf this area, which is a country on both sides with no in-between, then you get a potato chip, right? And that food is spread throughout the world.

And people eat more potatoes now than they ever have when it was, you know, a 19th century staple in Europe. And in part, because it's - they aren't eating it as, you know, there's mashed potatoes and others sort of - but they're eating it as french fries and potato chips. And it's just - it's eaten more than ever. And the cooking clearly is a transformation - a cultural way we've transformed foods to, you know, obviously, the great appeal there. Some of that appeal actually, though, is caramelization, which is sweet, and then sweet goes back to maybe some even more ancient appeals of looking for fruit.

DANKOSKY: Well, there's sweet, and there's crunchy. What about salty? Does salty and crunchy go so well together? Does everyone like salty?

ALLEN: Salty definitely has a baseline appeal across, you know, cultures. I mean, it comes in very young in developmental studies. And so, yes, it's one of the other buttons that we push. Some of the other debates - the one that sort of is fatty. Is fatty its own - like is it a century - something that has a real basic appeal. The other one is umami, which is savory, that also is one of these other sort of, again, sort of fundamental taste profiles. Bitter is also there. And that's an interesting one because we all have bitter, but in Western culture, bitter is a kind of marginalized flavor, right?

Everyone - I mean, people who drink coffee are making use of bitter and are enjoying bitter. But otherwise in the cuisine, bitter is not very acceptable, whereas in some Asian cuisines, bitter is really another flavor profile that's used.

DANKOSKY: Now, the foods that we evolved to eat, have they changed the way that our brains actually work over time?

ALLEN: Well, it's - that's a great chicken-and-egg sort of question is - or is it - in order to have our - to get our brains to changed how they work, do we have to eat differently - is the way most people would approach that - in the sense that one thing that happens in evolution is that we got much bigger brains in a relatively short time. It's three times larger, say, than in other great apes. This has happened over the past two million years or so. And brain tissue, nervous - neural tissue is expensive in an energetic sense.

It takes a lot to keep it going. And so one of the ideas that's out there is this thing called an expensive tissue hypothesis, is that there's been a tradeoff in terms of the size of our gut for the size of our brains. And when you make the gut smaller, you have to - you have less - it has less to it to extract nutrients from food. And so you - the idea is you have to eat higher quality food, more densely caloric or nutritional foods. And, you know, people tie this to eating meat, mammal meat, stuff that's on land.

Some people really like the idea of expanding access to marine animals too, and that's often for a very specific nutrient. So at any rate, there's an expansion of the diet that's related with having a big head.

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DANKOSKY: I'm John Dankosky, and this is SCIENCE FRIDAY from NPR. Let's go to the phones. Matt is calling from Lexington, Kentucky. Hi there, Matt.

MATT: Hey. How is it going?

DANKOSKY: Good. What's up?

MATT: Good. I'm a very picky eater when it comes to textures, and it's been an issue growing up and, you know, in social situations. But also crunchy is one of the textures that I found that I like across the board. In fact, some things that people typically don't have cooked as well done, I like to cook well done. And I'm wondering if your guest has any input as far as the historical - I don't know - thing regarding to that.

DANKOSKY: Yeah. Research on pickiness maybe, that's a good question. Thanks so much for your call.

MATT: Yeah.

DANKOSKY: John Allen?

ALLEN: Yeah. That's - that is pickiness is an interesting question. It's - one thing - if you look back over evolutionary times, or even in historical times, is that pickiness is to some extent an - I mean, is made possible by affluence. That is, if you want to limit the number of foods you eat, well, and then you - and you can do that if you don't - if you can always get access to it. And a lot of high quality foods, you know, would be highly seasonal or - and limited quantities and so on. So you can - it's easier to be picky now than at any other time in our past if you're in a nice - if you have a nice, you know, reasonable income and your access to a supermarket and so on, then you can choose to be less omnivorous.

That's sort of a paradox there. But, you know, the variety and steady access makes pickiness possible. Now, you know, pickiness then goes down to, well, what's the most highly appealing thing that you like. And if you're - have always have access to the most highly appealing thing that you like, then why not eat it. I mean, that's - it's a very rational thing to do, actually. It's like that if I like food A, wow, I'm going to eat that every day. Now, it may not be the best thing for you in a long-term physiological sense. But if it's got adequate calories, you know, it's not - it's probably not going to kill you. So, yeah, pickiness is an interesting thing.

DANKOSKY: Well, one of the things we choose to eat sometimes is a spicy food, something that actually hurts us. Why would we choose to eat something that might even hurt us?

ALLEN: Well, that's an interesting question. I mean, the one thing to keep in mind about that - especially talk specifically about heat in terms of spiciness, is that heat - the perception of heat is not salty, sweet or bitter. It's actually pain. And in contrast to those other sorts of flavors that, you know, qualities of foods that we eat, you can't - you don't habituate to it at least in the short term. When you're eating, right, and I've, you know, I've accidentally eaten incredibly hot things at, like, a Thai restaurant, and I'm dying.

And the last thing you want someone to say, oh, just eat a little more of that hot pepper, and you'll feel better. That's not true, right? You'll just feel worse and worse and worse. So getting past that...

DANKOSKY: Yeah.

ALLEN: ...is an amazing thing. And the standard - some of the things is that people over time can definitely habituate to pain. And so there are studies done on all sorts of different but not necessarily mouth pain...

DANKOSKY: Well...

ALLEN: ...but - OK.

DANKOSKY: ...if you want to learn a little bit more about all the different ways and things that we have eaten, John Allen's book is "The Omnivorous Mind: Our Evolving Relationship with Food." Thank you very much for joining us.

ALLEN: Oh, no problem.

DANKOSKY: Now, coming up after the break, we'll talk more about taste, the secrets of making a better-tasting supermarket tomato, one of the more complicated flavors to master. Stay with us.

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DANKOSKY: This is SCIENCE FRIDAY from NPR. Transcript provided by NPR, Copyright National Public Radio.